How do I add a list of things into a set?
When I do set.addAll I get an error
required type :Collection <? extends List>
provided type :List
public static Set<List<Food>> getAllMealPlans(Set<Food> foods, int numMeals) {
Set<List<Food>> set = new HashSet<>();
List<Food> aList = new ArrayList<Food>(foods);
List<Food> sortedList = aList.stream().sorted(Comparator.comparing(a -> a.meal)).collect(Collectors.toList());
set.addAll(sortedList);
Set<List<Food>> set = new HashSet<>();
This set object is a Set of List s. This means every item in the set is a List<Food>.
How do I add a list of things into a set?
As you want to create a Set which contains multiple lists, you can simply use set.add(). This will insert the sortedList as an item in the set which will end up what you are looking for.
set.add(sortedList);
Adds all of the specified elements to the specified collection. Elements to be added may be specified individually or as an array.
As you are already using java stream, I will get rid of aList variable like below.
List<Food> sortedList = foods.stream().sorted(Comparator.comparing(a -> a.meal)).collect(Collectors.toList());
You can actually remove stream operations. First collect set items to a List object and then perform sorting with a method references in your comparator.
List foodList = new ArrayList(set);
foodList.sort(Comparator.comparing(Food::meal));
